Lochinvar 90, 500 Pressure Only Relief Valve, Water Flow Switch if equipped, Thermal Expansion

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Installation & Service Manual

7Domestic water heaters (continued)

Relief Valve

RELIEF

VALVE

FLOW

SWITCH

Figure 7-8_Relief Valve - Water heater

Figure 7-9_Water Flow Switch, Water heater

This appliance is supplied with a relief valve sized in accordance with ASME Boiler and Pressure Vessel Code, Section IV (“Heating Boilers”). The relief valve is mounted directly into the heat exchanger inside the header (see FIG.’s 7-8 and 7-9). To prevent water damage, the discharge from the relief valve shall be piped to a suitable floor drain for disposal when relief occurs. No reducing couplings or other restrictions shall be installed in the discharge line. The discharge line shall allow complete drainage of the valve and line. Relief valves should be manually operated at least once a year.

Pressure Only Relief Valve

This water heater/hot water supply boiler is normally supplied with a temperature and pressure relief valve sized in accordance with applicable codes. Units may be supplied with an optional pressure only relief valve. When a water heater/hot water supply boiler equipped with this optional relief valve is piped to a separate storage vessel, the storage vessel must have a properly installed temperature and pressure relief valve which complies with local codes.

￿ CAUTION Avoid contact with hot discharge water.

Water Flow Switch (if equipped)

A water flow switch is available as a factory supplied option on all water heaters. The flow switch should be wired between terminals X and B. Remove the jumper between the X and B terminals on the terminal strip. This wiring connection installs the flow switch in the 24 VAC safety circuit to prove water flow before main burner ignition. A flow switch installed with the factory supplied minimum adjustment setting requires a specific minimum flow to make the switch and start burner operation. The flow rate required is a function of the diameter of pipe and tee used for installation. Ensure that the pump installed water heater will supply adequate flow to make the flow switch contacts and operate the water heater.

Thermal Expansion

A relief valve which discharges periodically may be due to thermal expansion in a closed system. A hot water supply boiler installed in a closed system, such as one with a backflow preventer or check valve installed in the cold water supply, shall be provided with means to control expansion. Contact the water supplier or local plumbing inspector on how to correct this situation. Do not plug or cap the relief valve discharge!

Cathodic Protection

Hydrogen gas can be produced in a hot water system that has not been used for a long period of time (generally two weeks or more). Hydrogen gas is extremely flammable. To prevent the possibility of injury under these conditions, we recommend the hot water faucet be open for several minutes at the kitchen sink before you use any electrical appliance which is connected to the hot water system. If hydrogen is present, there will be an unusual sound such as air escaping through the pipe as the hot water begins to flow. There should be no smoking or open flames near the faucet at the time it is open.

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Contents Models 90,000 500,000 Btu/hr Contents Checking equipment Please read before proceedingCodes Copper-fin =B=R Rating RatingsCopper-fin Specifications Gas connection pipe Copper-fin How it worksModels CWN270 Front View Model CWN399 Front View 422 Location of unit Determine unit location3Combustion Air Direct from Outside Determine boiler location6Combustion Air from Outside Single Opening Minimum Recommended Combustion AIR Supply to Equipment Room Vent Pipe Sizes VentingConventional Negative Draft Venting System Venting Less from Ridge From Parapet Wall Vertical Vent Termination ClearancesVent Materials Masonry Chimney InstallationSidewall Venting Number7CB with Vent Damper and Vent Damper Terminal Block Automatic Vent DamperGas Supply Gas Pressure Test Gas connectionsGas Connection Manifold PressureGas Piping Install Piping to ControlClockwise to raise regulator gas pressure, counterclockwise Gas Manifold Pressure Adjustment Procedure4Gas Supply Pressure Checking Gas Supply PressureTwo Stage Burner Control System Combination Gas ValvesVenting of Combination Gas Valves Relief Valve Water Flow Switch if equippedHydronic piping Low Water Cutoff if equipped Typical Heating Boiler InstallationsMinimum Required Flow For Heating Boiler General Plumbing RulesPiping of the Boiler System System Temperature Rise ChartCirculator Pump Specifications Heat Exchanger Pressure Drop ChartWater Connections Heating Boilers Only Circulator Pump RequirementsPrimary/Secondary Boiler Piping Boiler Flow Rates Three Way Valves4Primary / Secondary Piping of a Single Boiler Primary / Secondary PipingNot to Exceed 4 Pipe DIA or MAX. of 12 Apart 8Multiple Boilers Zoned with Circulators Boiler Operating Temperature Control Terminal Strip WiringPower Venter Connection to Terminal Strip Electrical connectionsOperating Temperature Control Temperature AdjustmentPump Wiring for a Heating Boiler Temperature Control Settings Locating Temperature ControlMaximum SET Point Determination Maximum Set Point DeterminationInlet Water Temperature Sensor Temperature Control SensorsMulti-Purpose Temperature Sensor Outdoor Air Temperature SensorInstallation of a Tank Sensor Water Heater Application Outdoor Air Reset OptionInstallation of a Remote Sensor Boiler Application Additional Temperature Controls Manual Reset High Water Temperature Limit Control Blocked Vent and Flame Roll-Out / Flame Interlock SwitchInitial Start-up Pre-start ChecklistStart-up 1Gas Valve 90,000 270,000 Btu/hr Models Lighting InstructionsTo Turn OFF GAS to Appliance Safety Shutoff Test For Standing Pilot Ignition SystemOperating Instructions Intermittent Pilot Spark Ignition System F9/M9 Safety Shutoff Test for Spark Ignition Pilot SystemFreeze Protection To Turn Off Gas to ApplianceFreeze Protection for a Heating Boiler System if required Water TreatmentRequired Temperature Rise Required Temperature RiseDomestic water heaters Domestic Water Heaters 90,000 500,000 Btu/hr ModelsPump Operation Water ChemistrySoftened Water Systems 1Single water heatersingle tank 2Single water heatermultiple tank 3Multiple water heatersingle tank Thermostat Settings Remote Sensor InstallationMinimum Pump Performance Heat Exchanger5Danger Warning Pressure Only Relief Valve Water Flow Switch if equippedThermal Expansion Cathodic ProtectionService technician Maintenance and annual startupOwner maintenance See the User’s Information Manual for instructionsMaintenance Check Relief Valve Check Expansion TankCheck Control Settings Check All WiringCombustion Air Adjustment Perform Start-up and ChecksInspection and Cleaning Procedure Inspect and Clean BurnerHeat Exchanger / Burner Access Clear Area Pilot Flame Adjustment ProcedureInspection of Heat Exchanger Waterways Water Circulating PumpGas Train and Controls Review with ownerTroubleshooting Pilot or replace Schematic Diagram F1 Unit DiagramsWiring Diagram F1 Unit 90,000 270,000 Btu/hr Models315,000 399,999 Btu/hr Models Schematic Diagram F9 UnitWiring Diagram F9 Unit Diagrams Diagrams Page Revision a ECO #C06290 initial release CFA-I-S Rev a 09/10
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